CVE-2024-50214

In the Linux kernel, the following vulnerability has been resolved:

drm/connector: hdmi: Fix memory leak in drm_display_mode_from_cea_vic()

modprobe drm_connector_test and then rmmod drm_connector_test, the following memory leak occurs.

The mode allocated in drm_mode_duplicate() called by drm_display_mode_from_cea_vic() is not freed, which cause the memory leak:

unreferenced object 0xffffff80cb0ee400 (size 128):
  comm kunit_try_catch, pid 1948, jiffies 4294950339
  hex dump (first 32 bytes):
    14 44 02 00 80 07 d8 07 04 08 98 08 00 00 38 04  .D............8.
    3c 04 41 04 65 04 00 00 05 00 00 00 00 00 00 00  <.A.e...........
  backtrace (crc 90e9585c):
    [<00000000ec42e3d7>] kmemleak_alloc+0x34/0x40
    [<00000000d0ef055a>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<00000000c2062161>] drm_mode_duplicate+0x44/0x19c
    [<00000000f96c74aa>] drm_display_mode_from_cea_vic+0x88/0x98
    [<00000000d8f2c8b4>] 0xffffffdc982a4868
    [<000000005d164dbc>] kunit_try_run_case+0x13c/0x3ac
    [<000000006fb23398>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<000000006ea56ca0>] kthread+0x2e8/0x374
    [<000000000676063f>] ret_from_fork+0x10/0x20
......

Free mode by using drm_kunit_display_mode_from_cea_vic() to fix it.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/926163342a2e7595d950e84c17c693b1272bd491
• https://git.kernel.org/stable/c/df2b00685cd33cd85be8910c7d6d22c4ebbf18bb